SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c5cd92cc9f670f5e8d9993c4557119af5ca270ab267b0ab2f34d6c8a6a61273' 
  AND token = 'j4I1kbG2PuxgNuev9sfIkhtzwC/zgKpOh+3ueeUCKRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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