SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e91ace254ae70918ce8546e7c62cbaa641bbccc26cb42229cc8b5bd4f231624e' 
  AND token = 'xxwGkXNkYMRW8l6K7dhgU66rYOZDotBfjgFS2uihcJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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