SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4d4dad6083f01dd468bd50bda8a6934e23208d13f0fd27c98713ac129d281c2d' 
  AND token = 'YtNh2utFenyav1IzIQCzbehcgY206NRch5Pazvj1Exk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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