SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '91572ed76886e1860a3a1cdda57e5ca6c31d8b64040e87cc85fc2d83a7ad9acf' 
  AND token = 'FJGWEPtn64Jl69kLqIWdjWAMNItNE1Alxamdtk2XR4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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