SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be40a6f6c8132ea53c1d0ccf1f47fa1fb6bd9c35d904980e1b8a8e315debbdae' 
  AND token = 'Oer/1Blh1MgdCoeUjyaTZ4AjtWmIFfxVs6VgWwPlPw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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