SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81611feb9d6c16206f15af0b1efbbb4aea1c991d95c86ad5f98605f5ad929195' 
  AND token = 'owCyZHG5iGNJvcR2Yj9JJ+Dckn9hCvEEtLGEyTmbQtc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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