SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0038c8a13fed7ac798a5d9d52cd9f1340eef57448f4993f0ab37010eab322c1d' 
  AND token = 'u6NwgKLN99QWWl81w67TKuOOZLxSzlrSfQHnIGQYkqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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