SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34e54e9dc2d7ed66431e1bd69570c12569b1d326338d6833918f9447832def22' 
  AND token = 'ppWjQYARXhq5BhYKS7hzjKHbDVwfx98fqwxzGWNZBk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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