SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db827d46f5da1c5332047ce910883677962659a4e556157045301aaeeb83ced7' 
  AND token = '5e5iSRyn7RQA07a8toZBjWrLL79GdTLPm4egJloRqWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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