SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62c789285efd47a0c47cbdac75a8a3725556054eeb9d0c5ab93948fbd7c0f20a' 
  AND token = '0mLLNbfrhgHjuvOqKlsoTn7EkHRCvS73xfvk1vGiGqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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