SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd1b251de3d23420053588da152bf4db833fefac13309189b97690c1e22cce5c' 
  AND token = 'ELNhjn9ssaf14p2JEKu92IsMNKGTvAOn3wDTLD2fFqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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