SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55bc293165cb1917c385a377e43a0477d8ff4555b75c53b6ec4bdae868936fdf' 
  AND token = 'iCcWbm/XPWjhs5gGPnh+/twsJvUXSNC41Kt0RCoDy/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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