SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdf9b4972e714ef2e9831fa9eeb9b6b286227ed4baa1c49f6c1013683a8fa006' 
  AND token = 'uuPJZwBovU3hsRODGmJVrtnErZjzo0ZH8Qffm4DbaMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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