SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '76811413a9f24ccaf95f1473e9bad92d466b59b77f44612f773cb5fd48fdf223' 
  AND token = 'HY/cUrYBdp0FMwAbi9xzynDsMLS3/UhZtKbVFV246V8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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