SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '433ddee1e86a7009d53118261256a3d78e86f4aca63fe7c3c1fa1c692f7a3537' 
  AND token = 'vJhp+1kj/NLxAxiAKbKzIXYtqMkk08/gs7csBa1M8Qw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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