SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c3d63087736371f620545f2ffd95d76c2957b77ec9179dc68a5bf50c3d1fafa' 
  AND token = 'nCz5CqoxgmeicpGBUwsG89D8vOzmkTVJhpSwyj/3h44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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