SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '16fed44979585c8c1296ce9416a8ce2b90205b4ad5346943414784e6c3976422' 
  AND token = 'E+9xYGibC2llGeGsVlqndCih+VoXBWHwGwMFUmyVdRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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