SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '607f9473a3589334e69248968092146f46b97aebd2338a6ec7bd2e226cbb50c0' 
  AND token = 'vpbhSKC3saADFsq50FpOhhM6w5GYH+WMuL724TBCC3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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