SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfd496435d5d471c1c9b76f3835fc2f7e954613f830e3ea4aedfb3d9aaf197b9' 
  AND token = '9iEKqHAwVB7qPlvzkzKpJ+LjcRm1qwk4f+Ow6aMyw7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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