SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d2a9ad1371afaedcf2a9869a760a8488ce869be884765f538d720735b71f5df' 
  AND token = 'gs8Ejp3nMOUfTcpq+O4fhpmqHUi3zqbALrmWGQF8VqU=' 
  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"
    }
  }
}