SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '986f7a8731443771f90616b6e89d1356248cd11e43674bb228ab2a9565f772a2' 
  AND token = 'OWPSJU8rjAeplORlN2ZT3AMQXP9uw8xGvzUN+qfPgS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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