SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65e6003acc65733505131d6765298490aef098f100c33c6e43567e12bbe9e354' 
  AND token = 'zp/xtzH3sVt1SmwrgVNUHBH3rJy3+i4csKypIim2XnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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