SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd806b37fbe0433d6a2bdbabd70516512054de92b11d0dcda685f5daf5070fdbc' 
  AND token = 'IDkCDNG2/EJXvtveRE1vrQydKcP/z3PmyyLEYaPnCaU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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