SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f2fe1caf3fe86f36e158138c9ab63359d7a5fdbc35d4ad3eb1d2ac7229319dc' 
  AND token = 'DVCBljUD/izIS6NyvG/f+v+kk+/muHjw9K4nxWftuYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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