SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '155d13f79964466da6ebecd1021fd8085164d7ed0bdd249093b4ddc56c267264' 
  AND token = 'g6vxjE36ik4szn4cdGpQZ6OgdJdwaIjsFwjvJOiQI+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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