SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5946f454b9f2946f9a2dfeca095996a04daac6ef5b183de17eb5f715d2325963' 
  AND token = 'YgqeUCpPttejzzhovXRa6GZ/WqGD/z/Avr0Cdzbsmb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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