SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6dd15b992daa6f94251c59f76acc99a69c1891ad6e31a795fe0617f199c11fcf' 
  AND token = 'fi4B3Y99eI3mhtQ81MCfGDd6cPjUKXjxjLtIg1erBfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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