SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '28700fc333c7433634f5c04cbce3ccac9eedfd4ff7a1680cc34103ba108cc79f' 
  AND token = 'MEokSoRVS3BkFJCF4yvQ8L439iIHSpgKr9cs855zovU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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