SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0d15fe90b3a3e10288d0b003807660417b4bec20336ec09272ee68e8ae9dbb4' 
  AND token = 'O31CkHNr9TbAkcjbt6CQAfrm9QIBMLbXhA77LzK0um8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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