SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4add9f027e088da16e6c7791202a36c6804aaa1d73ab7da9da20dc1898b136d7' 
  AND token = 'Qk6SrSABxidti8oLSskrVpKEcm6+nfdgobcI00NJ0Ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}