SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6499855b17b245caa4fa8b49491500821662e07aa12a440b3313f94d342cce19' 
  AND token = 'kSw+EBEnfr7aScMuuvmZgoHaDi9blunZwJ+GF1sWxE0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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