SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '554c4af248b999610a34d61c6a4745169b8003bc4b8c17969a1c5dff14861960' 
  AND token = 'wQw41atfym4/Nv1sG4FnSfgp4qc+ETBKDByRR5liZBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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