SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49a3667f98a1fa3fe01775c7710e4ecdb7f960e1474deec176740f8ae93b9942' 
  AND token = '79C3v7grPUN8tp2d40W48fc3R4I7WuIiCYJHoJL0Od0=' 
  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"
    }
  }
}