SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '981bcddf96ef490bd4d22c615ee3688230c1d64e61ad75a7847f506404932c63' 
  AND token = 'x6NSYWgQgX4YYiLrUAXrdTpDW1duKiesSJEIa++Dn0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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