SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69402ce73ce93433b07bef585ea77244f85e5a01d5d017b5241380ee99367ba5' 
  AND token = 'Qs/nabw1pPYEDVJWNIHtCHcg9nxOIFvoxqbTShs3EdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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