SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f54a5f8fca6b00367038c5ec447005fd9569e74947684149e3f9d181314bd53' 
  AND token = 'M3Adqu4E6J7jOVjRK3KySwiVSRlp5R3TPzN5nPTsEW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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