SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b7e360c32e94b411025e9e483141a25257b5cf2641375b54313ce8d6ef15f75' 
  AND token = 'Dunn2s1uowsRYuKOlNE2/KlSCMRL5wOrprw7Mb67uMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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