SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51cba8d94347e42b837c672e1aad63b20ece867beef51128ccc668817910033f' 
  AND token = 'KRZGXsc5X7PQ8Vu2rBxglQ+9FCqhR+VuLnyiIxXlk8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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