SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '031c62aed2374f87c205057dbfea1dac555a5d63f11fb1e5abf0dc27a6aa80e3' 
  AND token = 'NjetcCACB9yvrXXJYtebynMuoNmQUxBU0SFkNcJtggs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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