SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f875871162d865cb2f41d36bf1f0565371ddfc84abf636730dcfc75fbd4b06d5' 
  AND token = 'y5ROrz7B4LVy9AYUNl6m+Q5YtmF3iPtseiy3yWNzRWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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