SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b0823224beedaa236d300774e4046c97d76109f7b6b18aa834eeaaaee215c31' 
  AND token = 'XhkYXMGIBTjfmVcjM8mTRyPErGYLUTdtCJdQP+Z/l3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}