SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8d03f9eb39ec0219ae51b75a4e60511ecf4053c6fb02528510928219b9c2cf6' 
  AND token = 'vD8ysBLYWDZHyQl1A7S3qLksjCAxkqKKSlqVJOMa4F0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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