SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7699b74d72bb231f4e00292d08707d4b2920ad789e05ce84030755fd1ac71a28' 
  AND token = 'vbXmhEs2FTSmyW1T7xvObXnduf+A3HorIy6ahC7WqlE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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