SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b48e4a1eba6dbe699c20159576ca2d968f5def27e44008deff34cf765a85f37' 
  AND token = '0g++pMxF5OY18VcGlnZRm9qSKwqt4bq5oTP5SCPdVrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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