SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afb46d5aa0c32d5d5ce8652108a2b6ecc458090e5f3573b0fbbf3a5b03321543' 
  AND token = 'nCmISuxxZUlE1uqcRFWkNWoQS+/JAxkIN+pew+Hi12c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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