SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '908fd96d229e8c207c5f4864b506749ba3289bd4deeb2710795e3ce7adbab042' 
  AND token = 'rC3gSMQL5ixRmLIvdDQF8MZQalERuH/BzmQ7/vIfPh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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