SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '30d6fae73414810fafed6787efd106ecab7394db437fd0a3855b64eba5b65998' 
  AND token = '6RD77CUYWRqdx9pzcd+zoTuprQXZiCP3DiTpAdUZbUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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