SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a5e41be58f76566452c3cabea910d9252ce00d05146a4c722e4a39ee6414420' 
  AND token = 'gJ3cqWe6D+adOYrnwpdCxa/CWFhZbhEJR3139sE8LrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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