SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd310452fcd2611bb33661d78c2c3a2ec9314f57045016325ec2783ac7006f0b7' 
  AND token = '2qnzUR+ZbpN1bkohWJ78YsRBe0D7ENeZa2uLKDOXctI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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