SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5add2bfe2a83f5b33570469ed38b6617047a3e53e5839970492dd066e0360f0b' 
  AND token = 'cnFyyfDdiNADypIz6qF/dCKBkdUAnEOdHsl++2ig+nY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00102

JSON explain

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