SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e7623420f87597b0ada178810c2b78d702647e99067cd891cf1ec5d974d8d43' 
  AND token = 'bVtN8Zn2Gi86sBZLNIsN20495spnbT2wd5vHXrMqEm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}