SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0342e12d34bef59edfa79b8a351cddae7021165e2a007e58789a633d8348b2fe' 
  AND token = 'oCgehKJ4opIUjYjNnJ7tdL/xCIoB32KgYoKZ2XhmcDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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