SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0706f897913ba96a4bfdd912443e665e1dfadd77e78f7d6852161dd65a2bb210' 
  AND token = 'kbDRFpPyWEznl40yLBjuBfQa+fxLhdLdfmzyRRH2Uc8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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