SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7a908ea9270961ccb2295bccf442bc218ca43e37143fd34d291fe38d6885a49' 
  AND token = 'B6bxaGPyydyd4IgZFSIU3DKRlIcPiS009qeF4ifjxvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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