SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b94268b7838c71e75b560de2fc297012173c985d8bf1567847edd03e18eb7afa' 
  AND token = 'jH7yB533yETkZQyTjonuuOyxlFXwi0ovIivPUhbIOmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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