SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0386d70d8ac3cc6f04d01296159930d2177bf23927cc5c433dab3fe1cd25798f' 
  AND token = 'HOktJew66ObgewSw5mwIKjxfgax1U7JMdh1BXhH0ey4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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