SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ed1f66a61e756c36024bb53bf943a77433cd2363dcdce68e8bdd34a8711996b' 
  AND token = 'M0E+Ej/edE3QA/n19acpKtHCjzTt2DhYDWSkKqaCo4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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