SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34565dce676cc14ceee5e6943a793d490dfe17360920ecaa431e5a3852e0b923' 
  AND token = 'Can9H5fpCMcL+07ATtcJYOrIYngO8mPqHznDVuaiVdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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