SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c3e849df459fa01491cd9ad505811ff50038f2663d6fbef92bac39cbea5369c' 
  AND token = 'gE6olYvqYNbkMs1n9EQYpIbcIgD9LnD6JbcRS5XEmYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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