SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5b4ade037be9ec45ee6e611c4edcef211808b7e5cda80182d442f9d8410a7413' 
  AND token = 'EaK7+fupFT2iPuazytemOsbvTwAOaCnwPhUs+iFPnLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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