SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62321315483dcf96385f08121e6e0d69d01edb0cfbe2b7b789734fe065ad4bc7' 
  AND token = 'fA/8GoTyHgWwnRKyULIc/JxnFSclzQdrp4bNB+dy1GM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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