SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82a182aea4775778b6c0cb141126a75fce1c3d1b1d9185b91e530f2b7eac6eb5' 
  AND token = '5pO3HKcLV0Grg7PwYBT2mEQM89Ja3Ef1KsKN+rXqJx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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