SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46185f830ba3da6951b7777d20d1a4c3ddf5b6f339fe1cfd4ca46f666ecee94b' 
  AND token = '5TGaep7TZPuH4eRWeQrm4FNaE4XMPZWsPgJcbgVMBSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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