SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '881c9ab9a66a05e101516b640c0ea418c0be850f64dda959f198d1208fac8f9e' 
  AND token = 'nBW2EzjxpQ0HZ0Vzk7vmvL9LrNAy4GptvibFLYA0Qk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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