SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '07d6639718e4c82332acb143e0adc49583208390cce67007161039789747040b' 
  AND token = 'CqsEN1P9WYiJCt8MKwdDmfNEmvmkZFaMEIkwWHps5d0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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