SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '838b67860c7d1416d1c346e0989f3ed60f63dc58a7a9195185e6b950f048975e' 
  AND token = 'ZfRlhdHWjryXe5woFswxLz2avkIGMubtvfCV3qMHNbc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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