SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df5d350fa871e352d82625b0d4e9049d386a22e155c273c75ac783e0256beb8e' 
  AND token = 'qz3EdwcyqK/Uk+MxlmUOGxqShSyN/wB4QkJFaYvKzag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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