SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83f4d75b01d4151da322d1096ad6186e996e80012ab0fbf095e767eb24193aac' 
  AND token = 'orPcol9CK86DJpBbHcK+h6H36+pZXunhbSI1+vZuu7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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