SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2456c855683638910ce13f4fbd6ab9814399e797d009a117b01a7ce3c2a21ee5' 
  AND token = 'hQ71g5DImrkVMm3gfYCMF/l2K2t9hjYrls4hzDTM+Lw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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