SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ee48be372ce8d392ee3a0773dfe8509cf6eeb258f5b98b7c6e0c6ddde6373ba' 
  AND token = 'nXk2eHFW/OMQH4AnuuD6yJzBwwV0prLLZCxHAWoy1rI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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