SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89ecfac46bd397c0cd66781aba1264728dad17e76bb4266ed0f88dde0fd4e3f8' 
  AND token = 'wHf8iroCKIKfKaOPh9ogGJtWVsYmg4TeQiRTGQJrosQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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