SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b730ed790b0e8c8e1521e36cc13e8706c5c2975c0a6a84d52b5e3a9d8f29b11b' 
  AND token = 'sgpqcg0CTYffqIW/lIwYy+Jouxji3tzp17iuJVwVB6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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