SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9938f480fbc5092f33e1306e15c7021922d56738e351e48472fec3f86e9e7b4' 
  AND token = 'VqmaLO0YOKtTEIMhrATDDv6YBVi137AuY4yBPNQsecw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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