SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a276ee00d1d827314e560607866119274eda357cd2589751a3fa4701f7da5d8' 
  AND token = 'AqNhQN8ui6LcbaSGaG1kllCrrJsTdI0SyP5NIgqaoWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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