SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3953e44aeebaa5306459693dba1c4f1942b1bf6b35bdc0a02aa167562d83cb5' 
  AND token = 'dLZkh6eQ3kVUWN+XBybIjnIwBO1vixsvbPldWsb495w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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