SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6495d95679b4b5a2a6ffed906c99b333467130931e5da90d0cbd6b5e29e78a84' 
  AND token = 'myF2cudJ1gXhVFak1o8qZieKjHDd0wB5kBHHTPfnhAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}