SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6430da99af2be6357cd4ed227e07483cfee9994abf8bd552f5e8078fb43fdfb1' 
  AND token = 'TjKrJGVQKWib4UlzCSXFSGJRXvEqsmBwoER985fvky0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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