SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68cb7cca665ec8781f018c71a1f92f4f62f8ddf428581dd6a667ea750c4a08a5' 
  AND token = 'fbr8AFnCJholptuEyd2Yr2VZzzmoG2/6nqFpfyB8lxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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