SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37686c657b718ce4c1eabe363132aba596c0978b0a484b4cc9da0c4300778c8e' 
  AND token = '7Ck7gIVyg2DvRoTTHMswwtGAQBYF8HFu5/BzmvRlGC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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