SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c24aae4484b8501f79617e87316f8ad911187dacb405a5dd95b05773a11a9607' 
  AND token = 'oJj2oDWIbuIQvxY3bAZk6HD/Iw7eO4CNGL9txnLfvGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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