SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '512dacbac360d16dcc2bd155dd4e3c149c16274d7c2096115e0d1530f438a2d6' 
  AND token = 'DI07MxRlgFW09HSNBldQizGaxOyQhWNRCR0jHQmQ+lA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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