SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8904aafb8981292d6029333282492bdab2672fed6bd4c95d451f437563fd09f3' 
  AND token = 'eKxtwdTtbtsTRNXO6T/6NmuK8Ote/c2GdbaxIQUINZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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