SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39e9bae258b6218989dfb37f92b4297f2de12d6153297951b02f8a0f48950e5a' 
  AND token = 'gIHvDoQow8orY4qohex6Q4sMEWgk5oxrsRRzBEUuhiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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