SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f721b935d72f6c9212fb19d319281bc9a154d03a3c4191837b2ed4ade3f37067' 
  AND token = '8WztjfcUdSUWMCV+JptjE3j3aN+P7PS9TPTrQs7d7qY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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