SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e103a5cdf37a4f52c6408bbe1775fb697a3f8387d1d69b5b7262442880b0c241' 
  AND token = '2jqcztVwLjyx9lGpkqqNLxQQtDJlWjKX7JYh05x+IMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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