SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a462d5303ab2475378c66714032c93a9a015840b44e23ec0f44c8251edff7389' 
  AND token = 'Ufb1KegjWh984BAfLM8qJ/j6QRznPgdIYcumSxLVo4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}