SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fac75ad5f90cc4ff116381a3ac7663740160a0ee5dcc9f73e19fdd95d951626' 
  AND token = 'tkdoC+8RjNNEdxSWJvfb8JNnOnDOSiheShUtJAp8vY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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