SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a39d7682d8ce6b9b7f9b47021ed490bafda026df9a202adeda9bd3959760c1eb' 
  AND token = 'p5VdtMZ6wI4af/TbvmlQ/FAOV3HMfUKLZgsupfkiY7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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