SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7a032cbe4a491118615b6fd46d0fe16531025c4722403a2072ae57028bb80a6' 
  AND token = '5ySzZv1OHVBQFYtD6/NkkVgeF+JeMKz1RJcCW5mhPN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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