SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a056646cc750744a6858767ad38a2d8fb57eb615916ab510f3a42dc177c68337' 
  AND token = 'YciYZ/CsT2eRYUBKeFhl+J60B6lNS6UVgF0YoXQPgOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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