SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '759f19d4a182966d8f7942e7e9426fd8222b50e6c76daaf2771ea7d10391d398' 
  AND token = 'HGUbDQxc1LUSOfZXOKHgSEZqzVvU4sUJ5CdseMFYvDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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