SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd83304b212a741b7bd0082a85620795fbbf171b45896502f3f08645654b4b753' 
  AND token = '5fVcmYi0LHJ5QbAoUIDfcQUf9Rl9s7lbI70182Qfb0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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