SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87f336fe73f6248fa1c2c289031a3dd28f90ffde6b738efc03ecb5d5b0f84226' 
  AND token = 'DHWLPTaH2H1vgpHy1iWWxdA6dyFbUKDvctmsbYLl6Yc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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