SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8546a2bc4eb2e5851fc6e75086e93dcfb8a6570f0d7672135506412606b826bf' 
  AND token = '5MKg7Rye3aLelFx7YHZA+SDjdsh+ZXtjqKgCezd6a+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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