SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11b7f37c28f5871b075f452c717337b6c6625a20fd12215073bb63498d914d96' 
  AND token = 'JWBg2XnwUEPa/gmm7xkM04uhxDydwHFrqjcQ4vtWRN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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