SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfff5c0d49076ec9b0dc5ec371ee76cf93d04f6b8e97e405f2178356e8ea0d86' 
  AND token = '/ApMR0QtszV0MBNpxyFfmFK/yp7CNX8/FQh9+oqhX8M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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