SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c19e0bb74871c23522335bc5883379fa80cff6252f2811c72273618bb3f2573' 
  AND token = 'Oc2DaAVKg1Ey3PUtWH+lYwLg5+b3lAJcJ7NrGZP4vYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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