SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db9e58134d6c5623e7a97a6e155ac514d2eb9c781f35787a62a20541817e0368' 
  AND token = 'T7e9c0LVQtL7UY1e3hbb+Hre5pvddhAINxBafJSISpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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