SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74acae4f702960f1f2b7aebacc42cdd3eb708695741b9beb728028dda3c5f79b' 
  AND token = 'tRB3G+PvnlF/eSBRMWOhfWI8Cerd39r6drKlW7+LzvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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