SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df8fe28e5ecb6cd75faa87b59c8bf722782d215ce6f983b77923b940fdfe3d66' 
  AND token = 'N2wq34rHbFl9LzpFQUtPdhcpHRQ8NV8eOnzfHXYB18I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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