SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8dfdbaaab5377917a5fad8dfb829fc76ae431235cdea12e171c97b8c5c4d95d' 
  AND token = '1+T975X9ScFM7XUG5FNDPWEfsShfkfUwUhh/lxd3SeE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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