SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5839bc9e5d7b0aff565842d0a6c287b1ff4ade1aa23c60aada8332e0111463f' 
  AND token = 'foVxWlQ1UPFOTw1XN/7QxPzTPJnD7mjlXqY2T9HAdqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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