SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9366ed12e4584081206c22c534f8b67418af2c7b412234bba0629a1af9851003' 
  AND token = 'NaosOIkRjtHiaFEctkkU0ykxoFX9UbYfEyTDwY1Vogw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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