SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3f964a9fb6efad5069403807b36b116787b1a5c556c4530a0985ead25fc4af0b' 
  AND token = 'HLwl0nMASHRdcqxEXVHeUpdUty0YYLrmsmZ+tq5jMME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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