SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '331bde52584e10b535e895b081d69d05c83bb25bd6c849416380a874c6a111d7' 
  AND token = '5ND6ctCKQW2JoEC/t98q3bqnojIj6YMcOufF8kMOVSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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