SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6b35b2c24bcaed03cd68106283765fcd04378669c5a8b69eb2308f93e0ddc13' 
  AND token = 'BhZREhdHRvWtDvxiZt3MzXaoEW6e9REHkWhpA9MpNx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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