SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '837284bb78426eb254d0fe135b9fcaef07ece8fb263f33ea285b3681f24400ee' 
  AND token = 'HTs/o4bdbkeu6nXwpaYgG/CfxlhuOsYyjHhwdCeSOuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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