SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '977f8fa3bd04ea5bc5475e11a192f3d85cc15544585c258b1f03c68551dc7df1' 
  AND token = 'Ll9GrVPAuIUkNGLYQSFtBM0qGuJPYHK4NUmmYvdCFRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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