SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e243e299086588633174fb07b226467f9c0f03f2d0bcf7db1838b2a943a1ee3' 
  AND token = 'K0w/SJ+S8aGhBGcOB8hBYayCRBylHpwa4dpqofUBh3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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