SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0dd531766e16964570a60b4f3f77b7b96113b22b88094fef04930d8cff586c7' 
  AND token = 'dK/wzXBjO40HCbtrSb4uOshgOF5GlnSv4BHb2DbEu5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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