SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd05781acd6b0bbeeb57272f5b7453e0f64f3873d8bfc8e53665db51f27d97983' 
  AND token = 'siyVHpvZtZ/MKZLdvCAm78M+RsHG5wc8JmTq13PBnGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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