SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '81f87bba779ce11673acfc19ea372af59ff35bfe13640c71b2231fc90b573a34' 
  AND token = 'vZNY0OvKTGjazDe/EzC3TYaKunz6eqqn/pqHiFo84jk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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