SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eace7f7bd0b9f0400d2457dd6e2ba1687684eed0e06e3d8d46a8b4a25664626a' 
  AND token = 'rpmwPUaCel7Ui0t7JO4qPAdgDCW0EgtzlPq99fJRjaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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