SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '320b30be901d67a0fc19382a6e3b07217fb796fac3475862658e77ec90ed9ffb' 
  AND token = 'EKHj0TXm0dtSRPnYKLa9eUlt3fNo/U/gdWrLTc6Vvu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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