SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8bd9896dc96b005ff1f1e631d14165373e24633bafb64c02c1ae6329c51476f' 
  AND token = 'qLQvek2mJOxh8LD79HuH8w2z6575R2nRVYKim2apTv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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