SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2dd29a8158163f946ee10397e118ea05fd8a120d9aca0860016659225dbb7b03' 
  AND token = '10su3lPA4Mul1BPac/V/Znn7TWgpl3QjqDc+wDV4Ig8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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