SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f45e220a72be8aa606901861ee2741e3ca78026ecb78fd2340d55d34daa7f49' 
  AND token = 'vffa1NRyoo9++cSKMB/421hAPmx2lorVJMe7Jf6kTEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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