SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf8346bd132616ac9c968ef134f2df72ee612c73de6b7cd9f0df53fbb0a5be79' 
  AND token = 'mqiVz/oaoa9MXTa6AN+JGDYt0XVvfGZZsY1MnCo0Ids=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}