SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bf25beabb22b2302c3352f0f0b0ad2d15d7d0922e1cae8dca8c608091bed5d9' 
  AND token = 'losij4lsuKTkO6zIe+IdXyAqXDAWgv1jLg6SG0pb83w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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