SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee37991caa0154361b42e94b960512a85f7f2a0a474d453f620e9ef737a115d3' 
  AND token = '9aEXIfXXQKfsTQWsr4rjpuETM6tHVRmbzUQ8wg1rTLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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