SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4586aaca8ec629709e8e4f1426dac812bb7129282c7f6b75eaec95eec438398' 
  AND token = 'SGWxRk0bxL/UngXPF67wTkGWvXErLQhMBV0/UcbPFZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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