SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1d13dd5f283c96b7bad48df01ce1900068a76687afa980c0814c628edc8ef76' 
  AND token = 'yfYUT4Qbc/xdTJ/lFx2fp6Oh7ttBuhYOnRdSfCPCjP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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