SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a2cd1d1aa0ecd8a3e4f73daf94dcd40b4dd23c8d993884155dea15608caed8b' 
  AND token = 'x0rImNilAChnQiyZySLTT1HzwMOjHebpjXeu+3Ilm2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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