SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '60c76f7080d39915aa0167208f06bf2529ffbdaa88c08a7c85c7ec03c4be99b3' 
  AND token = '27/wUV6vOUBCGjreP+V7zfPdRWhw69QjYZ+tUF29V4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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