SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5618d48b0fa7b3d574b755a80438a0c33aafb1c195dd501f2541cf6f54faf496' 
  AND token = '9AUUC5OVJGPh4DDwGfkxmBscqdxPLx2rRa5aE4s1Wdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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