SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f0cd16b6af8898a8c035aa63b7b23e40c0381ca6815318aea07ae3c729c306ca' 
  AND token = 'kjX2+09nqciHV1G2WPy4AREdlWRHVMBgKAqZFe/zzHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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